The present invention relates to a valve-timing control apparatus for an internal combustion engine, in which opening and closing timings of an intake valve and/or an exhaust valve are controlled, and relates to a power-feeding mechanism that is used in the valve-timing control apparatus.
Recently, a valve-timing control apparatus is proposed in which opening and closing timings of an intake or an exhaust valve are controlled by transmitting rotative force of an electric motor through a speed-reduction mechanism to a cam shaft and thereby varying a relative rotational phase of the cam shaft to a sprocket to which rotative force is transmitted from a crankshaft.
Japanese Patent Application Publication No. 2012-132367 discloses a previously-proposed valve-timing control apparatus. In this technique, electric current supplied through a pigtail harness from a battery is supplied to the electric motor by way of power-feeding brush and slip ring only when varying a valve timing, in order to reduce power consumption as much as possible.